There's always a risk that something new is just around the corner.
Shortly after we received our S 100D last year, Tesla started bundling the high amperage charger at no cost with new 100's. Even after that was done, I checked with our service center - and it will still cost us almost $2K to upgrade our 100D from 48A to 72A (and that's only a software update! We already have the 72A hardware on board!).
We have some concern about this happening again with the X 100D we have on order, which is supposed to be delivered in June.
Musk indicates they could start rolling out V3 superchargers later this summer - and it's possible hardware changes will be needed to allow cars to take advantage of the faster charging. And if that happens, our X 100D could be one of the last cars built without the faster charging support.
But there's always a risk that's going to happen. If we waited until the fall, something new might be coming out later this year - and we could play that game forever, always waiting for the best car before we placed our order.
As an owner of one of the early Model S cars (vin 3xxx from January 2013), we went through this every few months with our S P85, as Tesla continued adding new features to the car (power folding mirrors, parking sensors, TACC, AP, ...) and we'd go through a brief period of feature envy - before getting back to enjoying our S P85 for the reasons why we bought it in the first place - it's still a fantastic car. Plus, it just got a new navigation system!
With Tesla's continuous improvement model, there will never be a "best time" to buy a Tesla - because Tesla could implement changes at any time. And even though Tesla is focused on the Model 3, that doesn't mean we won't continue to see changes to the S & X models...
If you like the features of the current S and X cars - buy it. If it's missing a feature you want - then wait and see if Tesla adds it - or buy something else.
